Ebola virus (EBOV), a member of the filovirus group, causes severe hemorrhagic fever in humans. The Innate immune response is an important target for EBOV, and Dr. Basler's group has identified filovirus proteins that inhibit interferon-a/p (IFN a/p) production. EBOV VP35 (eVP35) and MARV VP35 (mVP35) impair IFN a/p production by targeting RIG-l-like receptor signaling pathways. In fact, EBOVs with impaired VP35 IFN-antagonism are attenuated in mice and guinea pigs indicating that VP35 inhibitors can be used to treat EBOV infection. Dr. Basler's and Dr. Amarasinghe's groups have also shown that EBOV VP24 (eVP24) and MARV VP40 (mVP40) proteins inhibit Jak-STAT signaling triggered by IFN a/p and IFND, thereby blocking the antiviral effects of IFNs. We hypothesize that small molecules targeting these filoviral proteins can be identified and developed into therapeutic and prophylactic agents that are useful for combating filovirus biothreats. They can be used alone to augment the production of IFNs during infection or synergistically in combination with therapeutically-administered IFNs or possibly with other therapeutic agents. This multi-project Center builds on these exciting findings and new assay development studies (Project 1) to identify inhibitors of eVP35, mVP35, eVP24 and mVP40. In Project 2, Microbiofix will adapt the assays to HTS format and conduct screening, confirmation, validation, and selectivity/cytotoxicity assays, and In conjunction with Dr. Ready's group at UT Southwestern, medicinal chemistry optimization, and toxicity/PK/PD studies. The screening campaign will apply 4 HTS assays (eVP35, mVP35, eVP24 and mVP40) to the Microbiofix (200,000 compounds) and ICCB-L (300,000 compounds) screening libraries to identify compounds that act as IFN agonists. Project 1 will characterize the biochemical, structural and mechanistic basis of inhibition by leads and optimized leads. The infectious core will evaluate the hit and lead compounds against infectious filoviruses In vitro and in vivo. Resulting small molecule Inhibitors may be developed to generate new therapeutic agents to enhance patient outcome in Infection as well as chemical tools to study the role of these filoviral proteins.